Walls are the assembly people ask about first and the one we most often advise doing last. On Fox Creek's housing, where about 75% of homes were built before 1991, the walls are shallow, they already contain batt and a poly sheet, and they are covered in drywall somebody has painted. That combination makes a wall job a renovation rather than an insulation job, and the honest conversation is about whether it is the right place to spend.
What is in these walls already
A wall of this period is framed at the dimension that was standard at the time, with batt friction-fitted into the bays and a poly sheet stapled across the inside face before the drywall went on. That assembly has a defined resistance and it is not catastrophically bad. What it does badly is air: the poly is perforated at every staple, every outlet box, every wire and every pipe, so air moves through the wall at the edges of the cavity while the batt in the middle does its job.
Spray foam cannot be blown into a closed wall
This has to be said plainly because the terms get mixed up. Spray foam is a two-component liquid applied to an open surface, where it expands and cures in place. It needs the cavity open to be sprayed and it needs room to expand, which is why there is no such thing as spraying foam into a finished wall. What can be injected into a closed cavity is a different family of products altogether. If somebody has been told their finished walls can be spray foamed through small holes, they have been told about a different material.
So the question is what is already coming off
That is the actual decision. If a wall is being opened anyway, for a renovation, for new wiring, because the drywall is damaged, or because the siding is coming off and the sheathing will be exposed, then it is the right time and the cost of access is already being paid. Closed-cell against the sheathing then gives a continuous air seal and vapour control in one layer, at roughly R-6 to R-7 per inch in a cavity that does not have much depth to spare, and the poly comes out because two vapour barriers with a cavity between them is a trap.
From the outside is often the better job
Where the siding is due for replacement, working from outside is worth considering. The sheathing is exposed, the interior does not have to be emptied and nobody lives in a construction site, and the junctions at the floor levels and the eave, which are the ones that actually leak, are all reachable at the same time. Done from outside, the air barrier can run continuously past the floor assemblies instead of stopping at each one, which is a genuinely better result than the inside approach can produce.
If the walls are staying closed
Then the money goes elsewhere and it goes further. On this stock the rim joist, the ceiling plane and the crawl space or basement walls between them account for far more loss than the wall field does, and none of them requires opening a finished surface. We would rather say that than sell a wall job that disrupts the house for a smaller gain than the alternatives would have delivered.
Who you are dealing with
Wall spray foam insulation Fox Creek is quoted, scheduled and sprayed by us. Our own installers are on the job, and the number you are given is the number we stand behind.
Wall Spray Foam Insulation Fox Creek: Common Questions
Can spray foam be injected into my finished walls? No. Spray foam needs an open cavity to expand in. Products injected through small holes are a different material.
When is a wall job the right call? When the wall is being opened anyway, or the siding is coming off. Then the access is already paid for.
Should the existing poly stay? Not where closed-cell is being used, because it provides the vapour control itself. Two vapour barriers with a cavity between them traps moisture.
How much does wall spray foam insulation cost in Fox Creek? It follows the wall area and the depth, but on a retrofit the opening up, the removal of the existing material and the reinstatement usually exceed the spraying itself.
How do I choose a wall spray foam contractor in Fox Creek? Ask whether they would do the walls at all given what else is undone in the house. A contractor who prices the walls without asking about the rim joist and the attic is selling the most disruptive item first.
Size the assembly with the R-value calculator, then get a free Fox Creek quote. More on Wall Spray Foam Insulation Alberta province-wide.